Quite common during pregnancy due to the hormonal changes in the body, as more blood moves around the body to supply both mother and child.
Commonly seen in hot/warm weather as the tiny veins under the skin/in the nose tend to tear easily, or even when one has a cold, as they blow their nose.
Small occasional amount of nose bleeds is not harmful to mother/baby; however large amount or recurrent nose bleeds needs reporting to health professionals for attention.